Syringe devices comprising a gear mechanism are known in the art and examples may be seen in WO 01/95959 and WO 03/080160. WO 01/95959 discloses an injection device for injection of set doses of medicine from a cartridge. The syringe device comprises a gearbox which provides a gearing between an axial movement of an injection button and a nut engaging a piston rod relative to a housing. A gear wheel transmission is established between the nut and the injection button.
It is an object of the present invention to provide a gearing mechanism which is more simple than prior art gear mechanisms. A further object of the invention is to provide a gear mechanism which enables a wider range of obtainable gear ratios as compared to prior art gear mechanisms.